The US and China are building a new nuclear-powered submarine, which will be able to reach deep under the ocean, and it is the first to be built in more than 30 years.
The US will spend more than $1bn (£860m) on the new sub, with the Chinese government paying the rest.
The sub will be capable of operating up to 50km (30 miles) deep, with a range of 3,000km.
It will be armed with nuclear missiles and can carry a range more than 12,000 kilometres.
But it will also have an electric motor and a submarine-launched cruise missile, so it could be used for underwater operations.
The new submarine, called the Advanced Concept 2, will replace the submarine-based Advanced Concept 1, which was decommissioned in the 1970s.
The first of these submersibles, the Advanced Submarine-Descent Vehicle (ASVDV) was commissioned in 1989.
It was a sub that operated under water, and was not designed to operate on land.
The ASVDV is still operational, and is one of the submersible fleet, but its performance has not been up to snuff.
It has been involved in accidents, including one in 2009 when it sank and damaged three other boats in the South China Sea.
In 2016, it had to be towed back to shore after a cable snapped in a storm.
The latest submarine is designed to carry a maximum of 16 people.
It is intended to be capable at least for a year.
The boat will also carry up to 12 nuclear missiles, and can launch up to five cruise missiles, or up to 15 nuclear-armed cruise missiles.
In addition to nuclear missiles that can carry multiple warheads, the boat will be equipped with an electromagnetic submarine-harboring device, or EM-HBD.
These can be used to jam radio frequencies and intercept satellite signals, and the submarine can carry up 100,000kg (220,000lb) of nuclear warheads.
It can also carry a nuclear-capable submarine-attack submarine, or PAC-3, which can carry an additional 12 missiles.
The PAC-2 can carry five cruise missile warheads, or 15 cruise missiles and a sub-launcher, and has been built by Northrop Grumman, according to The Washington Post.
It reportedly costs about $8bn (£5.6bn).
The latest US submarine is the SSN-1, a new generation of diesel-electric submarine powered by a new diesel engine.
It had been commissioned in 2019 and was initially due to be replaced by the SSNS-3.
In 2019, however, the US Congress ordered that the new submarine was decommitted.
However, it has been in service since then, with more than 2,000 subs deployed around the world.
The SSNS3 is powered by the same engine as the new US submarine, the SSNH-1.
It also has the same propulsion system as the SSBN-2, and that will be the new power unit for the submarine.
It may be able use the new technology for some more operational deployments.
The submarine’s current US operator is the Naval Sea Systems Command (NSWC), which has operated it since 2021.
However it was not able to confirm that the US submarine will operate under US jurisdiction.
It remains unclear if the US is planning to use the sub in future deployments, as the US has not formally signed up to the Nuclear Proliferation Treaty.